The invention relates to an interactive network between one master computer and a plurality of slave computers, wherein the master computer comprises a master CPU, keyboard and VDU, and the each slave computer likewise, a relative CPU, keyboard and VDU. The prior art embraces a software independent device for connecting one master computer to a plurality of slaves, which is employed for teaching purposes; such a device comprises a master unit for the master computer, and as many slave units are required for the number of slave computers in use.
The master unit incorporates as many selector keys as may be needed to match the number of slave units connected to it, plus two video function keys, one of which used to call in copies of the students' screens, the other to broadcast a copy of the master screen to the students.
Each slave unit is provided with a mode key that enables contact with the master unit, and connects with the master unit by way of an individual cable; accordingly, the number of cables leaving the master will correspond to the number of slave units.
The instructor, using the master computer, can inspect the video image of any one of the students' slave computers, simply by depressing the first of the two special function keys together with the number key allocated for that slave station.
Depressing the second special function key, the instructor allows the students to see a copy of his/her own screen; this key simply enables the master-to-slave transmission line, though it is the student who must effectively access the master screen by depressing the appropriate key.
A device of this type is therefore substantially a passive visual system, pure and simple, and allows no interaction between the keyboards of the various computers. Moreover, a direct link-up needs to be established between each slave and the master, and a centralized system of connections is required.
An additional drawback of this device is its limited expandibility, inasmuch as master units are designed for a given number of slaves, and purchased as such; thus, a decision to increase the number of slaves at a future time necessarily involves nothing less than replacement of the entire master unit with one of wider capability.
Accordingly, the object of the invention is that of overcoming the drawbacks mentioned above.